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Back Focus Collimator for hire in uk?

P

Peter Keith

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I was wondering if any reduser in the uk knows of a rental company that hires out a RED focus or similar? I have both the TI PL mount and AL Canon mount. Last night I was using the Tokina 11-16 f2.8 to shoot fireworks. Its end stop is at infinity and I'm sure the image was still a little soft at infinity. Cheers for any advice!
 
Yeah back focus is a very common issue with the Tokina 11-16. You need to tweak it specifically for that lens or have it collimated by a professional.
 
We have an IBE collumator for PL camera mount. Youll need to sent the Tokina to a lens mantinence house to get it sorted. We generaly use Duclos or GL conversions which are factory set but do need a check from time to time. If its Nikon or EF then its more difficult to check the mount unless you have a collimator with EF and nikon mounts on it.
 
Funny thing was I'd borrowed it from a friend last minute for the shoot! I had ordered the canon mount version from Amazon Warehouse deals which arrived early on saturday morning...opened the box...they'd sent me the Nikon version...great! Box said Nikon but there was a barcoded sticker with Canon mount stuck on it...curious!
 
In the absence of a collimator I tweaked the back focus this afternoon using both hard stop zeiss primes and canon L zooms. I know this is far from ideal and I've most likely offset the back focus from PL set position but as I mainly use my own glass on the canon mount with my scarlet I'm now happy that the hard stop primes are as sharp as they'll be at infinity. As the zooms throw past infinity I can always find the sweet spot with them. Besides this, the zooms still line up with their distance markings anyway. Additionally, I know never to trust distance markings on stills lenses.

All the hard stop primes I mention are adapted contax to ef mount. Does anyone know if this would have an impact on the flange distance? Surely with the adapter, its been increased thus throwing out the back focus in the first place? Hmmmm?
 
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